Biosphere 2 experiment shows how fast heat could kill drought-stressed trees

		IMAGE: University of Arizona ecologist Henry Adams prepares to move a mature pine tree transported from New Mexico into Biosphere 2, seen in the background, for a climate-controlled experiment on how... Click here for more information.

Widespread die-off of piñon pine across the southwestern United States during future droughts will occur at least five times faster if climate warms by 4 degrees Celsius, even if future droughts are no worse than droughts of the past century, scientists have discovered in experiments conducted at the University of Arizona's Biosphere 2.